Answer: Clematis have only a few requirements: the roots need to be cool and the tops need to be in the sun. They thrive in rich, porous soil, and need to be watered and fertilized regularly during the growing season. Apply a complete liquid fertilizer monthly (follow label directions for dilution). If your plants are struggling, they'll be more susceptible to diseases. The treatment you've given to the plant under the porch may take care of the powdery mildew. The plant growing on the arbor may need pruning, as well, to help open it up to better air circulation, and to promote the growth of new stems. If you pinch the growing tips out you'll force new growth at the base of the plant. That should help fill it in and avoid a bare base. Armandi clematis needs frequent pinching throughout the growing season, to prevent the buildup of dead stems and vines in the center of the plant.
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